Recently, bio-diesels have been competitively developed and produced worldwide, and also domestically manufactured and brought to markets as an additive to petro-diesel.
During the production of bio-diesel, a large amount of glycerol, corresponding to about 10% of the amount of the produced bio-diesel, is generated as a by-product. However, supply of glycerol is greater than demand therefor and oversupply of glycerol decreases its value. Thus, it is economically advantageous to convert glycerol into dichloropropanol which is a higher-value added product compared to glycerol.
Meanwhile, dichloropropanol is a raw material used to produce epichlorohydrin. Most of the dichloropropanol which is currently supplied to markets is manufactured from propylene. More particularly, a method of preparing dichloropropanol includes a two-stage process of preparing allyl chloride through high temperature chlorination of propylene and preparing dichloropropanol by reacting the allyl chloride with hydrochloric acid using an excess amount of industrial water. However, the method of preparing dichloropropanol using propylene has problems in terms of instability of propylene supply and demand caused by increased price of propylene, generation of a large amount of waste water and other waste, excessive initial investment costs due to the two-stage manufacturing process and difficulty of newly constructing/modifying the process.
Accordingly, a single-stage process of directly preparing dichloropropanol by reacting glycerol and a chlorinating agent in the presence of a catalyst is more economical. The single-stage process using glycerol is advantageous in that costs of raw materials can be reduced by using inexpensive glycerol as a reactant, the amount of waster water and other waste can be dramatically reduced since industrial water is not required for the process, and thus the process is environmentally friendly, and initial investment costs related to the process and environment can be reduced. In addition, in the single-stage process of preparing dichloropropanol from glycerol, since dichloropropanol is directly prepared from glycerol which is a by-product generated in the preparation of bio-diesels, the single-stage process is more environmentally friendly than the conventional method of preparing dichloropropanol through the two-stage manufacturing process described above.
However, water is produced as a by-product using the method of preparing dichloropropanol using glycerol, and chlorination of glycerol may be inhibited by the water. Thus, the reaction rate may be reduced, a reaction time may be increased, and selectivity for dichloropropanol may be reduced as the reaction continues.